Heart rateThe number of QRS complexes per minute; note that HR may not equal perfused pulse rate. See also: - Step 1 Heart Rate - Rate - Rule of 300s (Triplicate Method) - Six Second Count - The Caliper Method 1.... is not always the same as pulse. Heart rateHeart Rate; calculated by counting the number of QRS complexes in six seconds and multiplying by 10; rate is also determined by measuring the number of large squares between two R waves; i.e. –1 large square = heart rate of 300/minute. is a measurement of electrical activity while pulse ensures the perfusion of the blood to the target tissues.
Many have been caught depending on the cardiac monitor for vital information such as heart rate. For example, patients with electronic pacemakers may display heart rates twice the pulse rate. This occurs because the QRS complexThe electrical representation of ventricular depolarization; the atrial repolarization is also a part of the QRS. ECG interpretation relies heavily on the QRS complex. The QRS complex represents the depolarization of the ventricles. The repolarization of the atria is also... produced after the pacer spikeThe telling sign that the rhythm is a paced rhythm; since the pacemaker spike is vertical, virtually no time was spent – this suggests strongly that the spike was initiated artificially and not organically (within the heart); note that a... also may count as a separate QRS complexA collection of waveforms (i.e. QRS complex and the ECG complex). 1. Six Second ECG Guidebook (2012), T Barill, p. 194, thus doubling the heart rate.
A special case of the disparity between heart rate and pulse can occur with ventricular bigeminyVentricular bigeminy is named after premature ventricular complexes (PVCs) that happen every second beat. This can happen with alternating sinus or junctional complexes so it is good practice to mention the underlying rhythm as well. The PVCs with ventricular bigeminy.... Ventricular bigeminy is a cardiac rhythmOften refers to a discernible pattern in time or distance between QRS complexes and/or P waves. with PVCs every alternate QRS complex. If the PVCs do not have a corresponding pulse, the pulse rate would be equal to 1/2 the heart rate displayed on most cardiac monitors. A seemingly adequate heart rate of 70/minute may have a pulse of only 35/minute!
Another example of a serious disparity between heart rate and pulse occurs with premature ventricular complexes (called PVCs). The PVCs come early and cause short filling times. It follows then that the ventriclesThe larger chambers of the heart (3 times the volume and muscle thickness than the atria), responsible for the pumping of blood to the lungs and the rest of the body. stretch minimally and subsequently contract ineffectively. The outcome: many PVCs fail to produce a perfusing pulse and the peripheral pulse is less than the heart rate displayed by the cardiac monitor (which includes both normal QRS complexes and PVCA wide QRS complex that arrives early is called a premature ventricular complex (PVC). A PVC has a width of 0.12 seconds or longer. The elongated period of ventricular depolarization is caused by an abnormal, less efficient pathway of ventricular... complexes).
The patient – not the monitor – is the gold standard.
This cannot be said enough. Most of us have been caught at one time or another relying on the cardiac monitor to the exclusion and great risk of the patient.
Heart rate is virtually always provided on the screen of a cardiac monitor. This number may offer some value but taking a patient’s pulse is always good practice. Don’t get burned.
1. Six Second ECG GuidebookA Practice Guide to Basic and 12 Lead ECG Interpretation, written by Tracy Barill, 2012 Introduction The ability to correctly interpret an electrocardiogram (ECG), be it a simple six second strip or a 12 lead ECG, is a vital skill... (2012), T Barill, p. 91